Q: After parked overnight, car loses all electrical power

asked by on

The first occurrence was at approx. 20,000 and has happened two times since then. I had driven 250 miles and left my car parked overnight on the street. The next morning there was no electrical power; I even had to use the manual key because the fob would not open or close locks. I then jump-started my car and it started with no problem. When I took it to the dealership, the diagnostic found no problems and no codes. Several months after that, my car was parked overnight in a garage, same as before… next morning no electrical power… jump-started yielded complete performance. No codes, battery was tested, voltage, amps, draw test - all were okay. One month later… same as previous two times! The dealer said he had seen this before in the same make/model as mine. It had been a loose ground wire and it solved the problem for the other car. The same dealer tested my car and no problems were discovered - everything was fine. Now, we have a car that we’re afraid to drive or have our family in it. Can you offer any suggestions, advice, experience, or Anything that might help me find the cause of this?

Hello. This may sound strange, but were you parked under a street light when the battery died? I have experienced faulty florescent lights putting out RF signals (the signals that your remote fob use) that do not let the car "go to sleep" and it drains the battery.

Today’s cars have a lot of computers and they use a lot of power. The car can detect when the key fob is getting close to the car and it will wake up all the modules in the vehicle so it is ready to unlock the doors when you get to it. The RF signals from the faulty street/garage lights will make the car think that the fob is still with the vehicle and will not let the computer modules fully shut down. Unfortunately, I am not aware of any fixes for this concern other than to keep track of where it is happening and avoid those areas. I would also recommend buying a small jump pack to keep in the car so you can get the car going even if you ever experience this problem again.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. After parked overnight, car loses all electrical power

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: The front wipers doesn't work

Hello. The best thing to do is to further test the system for the voltage supply. You need to locate the component or wire that is dropping the voltage. If the motor is not receiving any power on any speed...

Q: I replace the thermostat and was told to drive it for engine light to go out but its still on after 5 days what can i do?

Anytime a vehicle repair is performed to remedy faults that arise from a check engine light (CEL) diagnostic, at the conclusion of the repair, a professional mechanic uses an appropriate scan tool to turn OFF the check engine light. The...

Q: Car won't run due to electrical problem.

A load that stays on after the key is turned off is called a parasitic load, it must be tested for while the key is off and with an ahmmeter. Have a certified mechanic, like one from YourMechanic, test for...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...